Naming Binary Compounds (Ionic Compounds)
Rules:
1. Determine which element is the cation (+). The cations are usually found toward the left
of the periodic table and are written first in the name and formula of a molecule.
2. Determine which element is the anion (-). The anions are non-metals (or hydrogen),
located on the right side of the periodic table, and are written second in the name and
formula of a molecule.
3. Write the cation first using the name of the element.
4. Write the anion second, dropping the usual ending and replacing it with “ide”.
element
fluorine
chlorine
bromine
iodine
hydrogen
anion
fluoride
chloride
bromide
iodide
hydride
element
oxygen
sulphur
nitrogen
phosphorous
carbon
anion
oxide
sulphide
nitride
phosphide
carbide
Diatomic Elements
The following gaseous elements consist of two atoms joined together. They do not occur
naturally as a single atom. (mnemonic – HOFBrINCl or Hey NO halogens)
H2 N2 O2 F2 Cl2 Br2 I2
Write the correct chemical name for each of the following:
1. MgO
11. K2S
2. LiF
12. Na2O
3. NaBr
13. K2O
4. CaO
14. Ca3P2
5. AlN
15. H2O
6. NaI
16. CaBr2
7. Al2S3
17. MgS
8. Ag3P
18. ZnBr2
9. BaCl2
19. B2O3
10. AlCl3
20. Ba2C
1
Writing Chemical Formulae (Ionic Compounds)
Rules:
1. Write the chemical symbol for the cation(+) first, followed by the symbol of the anion(-).
2. Write the charge of each ion above each symbol.
3. Cross the charges, ignoring the signs.
4. Reduce the numbers if there is a common factor.
5. If the number beside an element is 1, do not write it.
(The total positive charge will now equal the total negative charge in the molecule.)
Example: silicon oxide
Rule 1
Si
O
4+
Rule 2
Si
O2Rule 3
Si2O4
Rule 4
SiO2
Write the correct chemical formula for each of the following:
1. sodium nitride
11.calcium phosphide
2. sodium oxide
12.sodium fluoride
3. calcium chloride
13.boron nitride
4. magnesium
sulphide
14.calcium hydride
15.hydrogen oxide
5. silicon oxide
16.aluminum nitride
6. aluminum carbide
17.potassium carbide
7. boron fluoride
18.zinc iodide
8. potassium nitride
19.barium bromide
9. cesium oxide
20.silver selenide
10.aluminum bromide
2
Naming Molecular Compounds
Prefix Method
This method is commonly used only for naming binary compounds composed of two non-metals.
Rules:
1. A prefix is used to indicate the number of atoms in the molecule.
number of
atoms
1
2
3
4
5
prefix
mono
di
tri
tetra
penta
number of
atoms
6
7
8
9
10
prefix
hexa
hepta
octa
nona
deca
2. Place the appropriate prefix in front of the cation (mono is dropped in the first element).
3. Place the appropriate prefix in front of the anion, using the “ide” suffix as before.
Write the correct formula for each of the
following:
Write the correct name for each of the
following:
1. sulphur dioxide
1. SI2
2. carbon disulphide
2. PCl3
3. nitrogen trichloride
3. SeO
4. phosphorous pentabromide
4. As I5
5. diiodine pentasulphide
5. SO2
6. selenium tetrachloride
6. Se2O3
7. bromine heptafluoride
7. SF6
8. nitrogen monoxide
8. N2O5
9. selenium trioxide
9. AsBr3
10. dinitrogen trisulphide
10. CO
3
Multiple Valences
IUPAC (Roman Numeral) Method
The IUPAC (International Union of Pure and Applied Chemists) method is a standardized
nomenclature system that always works. The Roman Numerals are NOT used when there is only one
possible positive valence (ie Columns I, II, III, Ag, Zn and Cd).
Rules:
1. Determine the charge on the anion (there is only one possibility).
2. Determine the total negative charge by multiplying the anion charge by the number of anions
present.
3. The total positive charge equals the total negative charge in a neutral molecule.
4. Divide the total negative charge by the number of cations present to determine the charge on
each cation.
5. Write down the name of the cation.
6. Write the charge on the cation using Roman Numerals in brackets after the cation.
7. Write down the name of the anion using the “ide” ending.
eg. Fe2O3
1.
2.
3.
4.
charge on O = -2
total negative charge = –2 x 3 = -6
total positive charge = +6
charge on iron = +6 2 = +3
5. name of molecule = iron (III) oxide
Write the correct IUPAC name for each of the following.
1. FeCl2
6. Au2S3
2. Cu2O
7. Sb2O5
3. Hg3N
8. SnBr4
4. PbO2
9. AuCl3
5. CuF2
10. CrBr3
Write the correct formula for each of the following.
1. mercury (I) oxide
6. tin (II) phosphide
2. lead (IV) chloride
7. gold (I) fluoride
3. iron (III) nitride
8. mercury (II) nitride
4. copper (I) sulphide
9. antimony (V) bromide
5. antimony (III) oxide
10. tin (IV) carbide
4
Compound Ions (Polyatomic Ions)
Many ions consist of more than one element. These ions all have special names which you will not
need to memorize. A chart of the compound ions will be provided to you for all tests and quizzes.
The charge given in the chart is the charge on the compound ion as a unit.
Compound molecules are named using the IUPAC system, the only difference being that if more
than one of the compound ions is needed to form a neutral molecule, brackets are placed around the
ion.
ammonium
NH4+
sulphate
SO42-
nitrate
NO3-
sulphite
SO32-
nitrite
NO2-
phosphate
PO43-
hydroxide
OH-
phosphite
PO33-
chlorate
ClO3-
carbonate
CO32-
hydrogen carbonate (bicarbonate)
HCO3-
eg. iron (III) sulphate =
Fe+3
SO4-2
Fe2(SO4)3
Complete the following table.
1. silver carbonate
11. Fe(NO3)3
2. calcium nitrate
12. AuClO3
3. lead (II) nitrate
13. Mn(HCO3)2
4. ammonium chloride
14. Sr(NO2)2
5. manganese (IV) chlorate
15. Ti(ClO3)4
6. potassium phosphate
16. Co3(PO4)4
7. lithium hydrogen carbonate
17. (NH4)2SO4
8. copper (II) sulphate
18. Ni(OH)3
9. zinc phosphate
19. Sb(ClO3)5
10. aluminum hydroxide
20. Sn(CO3)2
5
Simple Nomenclature
ions
molecule
molecular name
1. silicon oxide
21. MgCl2
2. boron fluoride
22. SiC
3. aluminum carbide
23. Al2S3
4. potassium nitride
24. SiH4
5. cesium oxide
25. H2S
6. aluminum bromide
26. Ag3P
7. calcium phosphide
27. H2O
8. sodium fluoride
28. MgO
9. boron nitride
29. CaH2
10. nitrogen hydride
30. NaBr
11. hydrogen oxide
31. KF
12. calcium nitride
32. C3N4
13. aluminum nitride
33. H2S
14. calcium oxide
34. B2S3
15. potassium sulphide
35. BaO
16. zinc oxide
36. ZnO
17. silver nitride
37. SrS
18. lithium fluoride
38. BeS
19. magnesium iodide
39. SiCl4
20. hydrogen arsenide
40. AlF3
6
Binary Nomenclature
1. Iron(III) sulphide
21. MgCl2
2. calcium chloride
22. SiC
3. tin (IV) carbide
23. Al2S3
4. carbon dioxide
24. SiH4
5. aluminum bromide
25. H2S
6. rubidium nitride
26. Ag3P
7. Copper(I) phosphide
27. H2O
8. antimony(V) fluoride
28. MgO
9. antimony (III) fluoride
29. CaH2
10. cesium oxide
30. NaBr
11. mercury (II) iodide
31. KF
12. lead(IV) chloride
32. C3N4
13. gold (I) nitride
33. H2S
14. zinc sulphide
34. B2S3
15. silver bromide
35. BaO
16. tin(II) oxide
36. ZnO
17. copper (II) phosphide
37. SrS
18. beryllium iodide
38. BeS
19. mercury(II) carbide
39. SiCl4
20. table salt
40. AlF3
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Compound (Polyatomic) Ion Nomenclature
1. copper (II) nitrate
21. K2CO3
2. iron (II) sulphate
22. Na2SO4
3. potassium chlorate
23. Zn3(PO4)2
4. zinc carbonate
24. Hg2SO4
5. silver phosphate
25. Ba(NO3)2
6. sodium sulphate
26. Fe(ClO3)3
7. barium hydroxide
27. Pb3(PO4)4
8. ammonium phosphate
28. Hg(NO3)2
9. lead (II) hydrogen carbonate
29. FeSO4
10. copper (I) nitrate
30. Sb(HCO3)5
11. mercury (II) sulphate
31. MgSO4
12. zinc sulphate
32. Ag3PO4
13. gold (I) phosphate
33. NH4NO3
14. aluminum nitrate
34. Sn(OH)4
15. ammonium hydroxide
35. BPO4
16. boron carbonate
36. Be(OH)2
17. lead (IV) hydrogen carbonate
37. AuNO2
18. ammonium sulphite
38. Cu3(PO4)2
19. mercury (II) phosphate
39. AgHCO3
20. antimony (III) carbonate
40. Li2SO4
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Nomenclature: A Little Bit of Everything
1. oxygen gas
21. NaClO3
2. magnesium chloride
22. Sb2O5
3. tin (IV) carbonate
23. Sn(NO3)4
4. carbon monoxide
24. Na2O2
5. aluminum sulphate
25. HgBr
6. copper (II) phosphate
26. Zn2C
7. copper (II) phosphite
27. H2
8. antimony (III) nitrate
28. Al2O3
9. argon gas
29. ZnCO3
10. ammonium hydroxide
30. Mg(ClO3)2
11. mercury (II) sulphate
31. Pb3N4
12. diantimony trioxide
32. AlF3
13. gold (I) hydrogen carbonate
33. He
14. beryllium sulphite
34. SO3
15. silver bromide
35. NaCl
16. boron oxide
36. N2
17. lead (II) bromide
37. Pb(CO3)2
18. barium carbonate
38. CO2
19. mercury (I) carbide
39. (NH4)2O
20. chlorine gas
40. AuBr3
9